1. Field of the Invention
This invention relates to integrated circuits and particularly, though not exclusively to integrated circuits for use in single or multi-processor systems.
2. Discussion of Prior Art
One object of the invention is to provide an integrated circuit, (to be referred to herein as a “Butler Chip”) which is capable of directly supporting the shared data and multi-tasking concepts of real-time networks in the context of single or multi-processor systems.
A further object is to provide a more deterministic (in the temporal sense) execution environment so as to eliminate some aspects of pessimistic timing analysis at the fundamental level of computer operation.
For a better understanding of an application of the “Butler Chip” to be described herebelow, reference is made to our co-pending Patent Application WO91/16681 (now U.S. Pat. No. 5,469,549). Therein, two Central Processing Units (CPU) are able to interact through an Asynchronous Dual Port Memory (ADPM). The ADPM can carry many communications routes (spatially multiplexed) such that there is no temporal interference between these routes, and where the temporal interaction between operations at the two sides of the same route is confined entirely to that interaction which is implicit in the protocol which characterises the dynamics of the route.
The latter property is dependent upon the fact that the ADPM has two completely independent access paths to every memory element and itself applies no exclusion.